Method of producing synthetic lubricating oil

ABSTRACT

A method of producing a synthetic lubricating oil which comprises polymerizing a mixture of C8-C10 Alpha -olefins which contains less than 30 mol % of C9 Alpha -olefin and having of average carbon number of 8.7 to 9.7 with the use of Ziegler catalyst or a ternary catalyst made from an alkali metal hydride compound, aluminium halide and titanium halide, and separating an olefin polymer ranging within the boiling point of the lubricating oil from the resulting polymerization reactant.

United States Patent [191 Isa et al.

[4 1 Sept. 23, 1975 METHOD OF PRODUCING SYNTHETIC LUBRICATING OIL [75] Inventors: Hiroshi lsa, Funabashi; Hajime Tomooka, Iohikawa; Yoshihiko Murakami, Yachiyo; Kenji Karube, Tokyo; Takeshi Inomiya, Tokyo; Masuzo Nagayama, Tokyo, all of Japan [73] Assignee: Lion Fat & Oil Co., Ltd., Tokyo,

Japan [22] Filed: Feb. 26, 1974 [21] Appl. No.: 446,018

[30] Foreign Application Priority Data Mar. 5, 1973 Japan 48-02635] [52] US. Cl 260/683.l5 D; 252/59; 260/6839 [51] Int. Cl. C07C 13/10 [58] Field of Search 260/683.l5 D, 683.9;

[5 6 References Cited UNITED STATES PATENTS 3,113,167 12/1963 Sauer 260/683.15 D 3,156,736 11/1964 Southern et a1. 5 D 3,179,711 4/1965 Antonsen 260/683.l5 D

Primary Examiner-Paul M. Coughlan, Jr. Attorney, Agent, or Firm-Woodhams, Blanchard & Flynn [5 7] ABSTRACT 6 Claims, No Drawings METHOD OF PRODUCING SYNTHETIC LUBRICATING on.

BACKGROUND OF THE INVENTION 1. Field of the Invention I The present invention relates to a method of producing a synthetic lubricating oil, and in detail to a method of producing a synthetic lubricating oil having a high viscosity index, high flash point and low pour point, and whose viscosity is extremely low at lower temperatures, by mixing a-olefins of different chain length in a proper ratio and polymerizing them. I 7

2. Description of the Prior Art I I There are many kinds of lubricating oils such as petroleum lubricating oils, synthetic lubricating oils, fatty oils, etc. The need for lubricating oils having a high .fla sh point, a high viscosity index and low pour poin t,.

etc. has increased. However, the petroleum lubricating oils which are now employed do not have all of the foregoing desired properties perfectly,

On the other hand, recently, in synthetic lubricating oils produced by organic synthesizing methods, .atten-.

tion has been paid to liquid polymers (olefin polymer oils) obtained by polymerizingolefins. However, the polymerization of olefins does not produce polymer oils having the desired high viscosity index when there are usedgeneral polymerization methods such .as cati- Ohio-polymerization, radical polymerization, etc'. which are accompanied by isomerization.,Therefore, recently temperature below 100F, a viscosity index of 130, a

the method cannot be employed as the industrial .pro-

cess atall- I SUMMARY or THE -11-1vi2Nrio1-1 An objectof the. present-invention is to .provide' a method of producing a synthetic lubricating oil having a.'high viscosity index, highflash point and low pour point and showing low, viscosity at extremely low temperatures..Another object of the present-invention, is to provide a methodof producing a novel synthetic lubrieating oil for which conventional production facilities ca be used.

As a result of many kinds of experimentsand'examiv with the ,use of a complex compound prepared from, a

titanium halide-and an alkyl.- aluminum compound selected from the group consisting of AlR AlR Cl, AlR Cl and AlRCl (R is an alkyl group), or a mix-..

ture consisting of an alkali metal hydride, aluminum halide and titanium. halide-as a catalyst, an olefin polymer having a boiling point within the range of that of lubricating oils is separated from the resulting polymerization reaction mixture, and a synthetic lubricating oil is produced. The ,method of producing a synthetic lubricating oil according. to the present invention is characterized by employing as said starting olefins,.a.mix-

ture of rx-olefins of C -C which contain. less than 30 mol of C d-olefin olefins and which have an average carbon number of 8.7 to 9.7.

As described above, the starting material-olefins used in the present invention ,are octene-l, nonene-l and decene-l andthose' olefins are properlymixed for use so .thatthe ratio of mixing becomes less than 30 mol of C a-olefin (nonene-l) andthe average carbon number becomes 8.7 to 9.7, preferably 8.8 to 9.2.. ln-.case' mixture of starting olefins is outside this range, the desired lubricating oil cannot be obtained. Also, it is not preferable to mix olefins below C -C in the starting olefin mixture, but if they are mixed, the allowable amount thereof must be at most within about 10 percent.

prepared by polymerizing C a-olefin ,and distilling fractionally has a tendency that the viscosity become too high at extremely low temperatures as the viscosity index is not so high, and both the flash point and tire point become lower. Also, the lubricating oil prepared by polymerizing C a-olefin and distilling fractionally has a tendency that the viscosity is suitable at low temperatures, but the pour point becomes too high. Moreover, when those polymer oils are mixed in a proper ratie, the merits of the respective polymer oils are merely mutually lost, and a lubricating oil possessing all of the desired properties has not been obtained yet.

It is reasoned that if those polymer oils are fractionally distilled accurately by' repeating the methods such as molecular distillation method, etc., there is the possibility that one part thereof will be used as the working oils for aircraft, but the yield is about l0. Therefore,

In polymerizing the mixture of those starting material olefins namely, a-olefins, either a complex compound (Ziegler catalyst) prepared from a titanium halide and alkyl aluminum compound or a ternary catalyst (metal hydride catalyst) consisting of an alkali metal hydride, aluminum halide and titanium halide is used.

When using a Ziegler catalyst, there can be used alkyl aluminum compounds, trialkyl aluminum (AlR dialkyl aluminum chloride (AlR Cl), alkyl aluminum sesquichloride (AlR Cl and alkyl aluminum dichloride (AIRCI As the titanium halides, there can be used titanium tetrachloride, titanium tetrabromide, titanium trichloride halides, etc. Two or more kinds of ,alkyl aluminum compounds may be mixed and used.

The alkyl groups of the compounds are not important and they are generally a methyl group, ethyl group and n-propyl group, but the ratio of the alkyl aluminum compound to the titanium halide is preferred to be in the range of 0.55.0 AlzTi mol ratio. On the other hand, in case of using the hydride catalysts, as alkali metal hydride compounds, there can be used lithium hydride, sodium hydride, potassium hydride, sodium borohydride, lithium aluminum hydride, etc., and as aluminum halides, there can be used aluminum trichloride, aluminum tribromide, alkyl aluminum dichloride, etc., and as titanium halides, the foregoing compounds have been known. The ratio of the alkali metal hydride compound to aluminum halide is preferably from 1 0.5 to l 6 (mol ratio), and the ratio of titanium halide to aluminum halide is preferably from 1 0.5 to l 2 (mol ratio).

The polymerization reaction is carried out with the use of a mixture of a-olefins whose average carbon number is 8.7 to 9.7 and in the presence of said catalyst at temperatures of to 200C. In case of using the hydride catalysts, alkali metal hydride compounds and aluminum halides are previously dissolved or dispersed in solvents such as diethyl ether, tetrahydrofuran, 1,4- dioxane, saturated hydrocarbon, etc. for activation.

The polymerization reaction in the present invention can be carried out with or without the use of the solvents. As the solvents to be used in the reaction, paraffinic hydrocarbons containing n-paraffin and isoparaffin, naphthenic hydrocarbons, hydrocarbon halides or mixtures thereof are preferable, and as proper concrete examples, n-pentane, isooctane, cyclohexane, dimethylcyclohexane, trichloroethane, methylchloroform, tetrafluoroethane, etc. are enumerated. In case of using those solvents for the reaction, the weight ratio of the solvent to olefin is proper to be in the range of l 2 to 4 1. While, in case of not using those solvents, the starting material olefin mixture itself is made to function as a reaction solvent, but it is necessary to take notice in the control of the reaction heat as the reaction proceeds rapidly. As the control methods for the reaction heat, a method of gradually adding the raw material olefins or catalyst, a method of forcibly cooling by outside heat-exchange, and the like are effective. In order to decompose the catalyst after the reaction is over, an alcohol or alkaline aqueous solution is generally used, but the use of an amine or ammonia is most preferable so that no halogen remains in the polymer. Unreacted olefins and olefin dimers are contained in the resulting polymer solution and are not preferred in the performance of the lubricating oil, and therefore, they are removed through distillation and extraction. Also, in order to improve the thermal stability of the lubricating oil, the remaining double bonds may be hydrogenated. The hydrogenation can be easily effected with the use of hydrogenation catalysts such as Raney nickel, etc.

As described above, the present invention is to provide a method of producing a higher synthetic lubricat ing oil having a high viscosity index, a high flash point, and a low pour point and a considerably low viscosity at extremely low temperatures, by polymerizing a mixture of C -C a-olefins which contains less than 30 mol of C a-olefin and having an average carbon number of 8.7 to 9.7 with the use of Ziegler catalyst or the hydride catalyst. According to the present invention, the lubricating oil satisfying all of the standard values in U.S. ARMY STANDARDS MIL-P183282 (working oils for aircraft) can be obtained with a yield above percent.

The property of the oligomer of each olefin is shown in TABLE 1 which is prepared by polymerizing with the use of Ziegler catalyst, distilling it to remove the unreacted olefins and olefin dimers from the resulting polymer solution, thereafter taking out 50 percent of fractional distillate corresponding to the lubricating oil, and hydrogenating it.

As shown in TABLE 1, in the oligomer using C C olefins as starting materials, if the viscosity at 40F is regulated within the standard, the flash point and fire point become problems because of its low viscosity index, and therefore, particularly the fire point will not be able to satisfy the standard even if any means is employed. On the other hand, in the oligomer using C, olefin as a raw material, the fire point and the viscosity at low temperatures are preferable, but the pour point is high, and further there is a drawback that a cloud point appeared at about 20F. Even if those olefins are simply mixed and polymerized, or various kinds of polymers are properly blended, the result does not satisfy the standard, and the lubricating oil that passes the standard of MIL-B83282 cannot be obtained as long as C -C a-olefins are not mixed and polymerized so that less than 30 mol of C a-olefin is contained in the ratio of mixing and the average carbon number is 8.7 to 9.7 as described in the present invention.

TABLE 1 s-m B 10 7 MlL-H83282 Hexene Octene Decene* Oligomer Oligomer in standard oligomer Oligomer Oligomer (carbon (carbon number 8.7) number 9.0)

Viscosity 2l0F (CS) above 3.5 3.95 4.04 4.09 4.00 4.02

Viscosity 100F above 165 I850 19.30 l9.20 19.30 l8.60

Viscosity 40F below 2600 3500 2800 2200 3000 2400 Flash point (F) above 400 380 4 l 5 440 430 442 Fire point ("F) above 475 420 440 490 460 480 Four point ("F) below 80 80 50 Viscosity Index TABLE l-continued tll(l CK10* MlL-H83282 Hexene Octene Decene* Oligomer Oligomer in standard Oligomer Oligomer Oligomer (carbon (carbon number 8.7) number 9.0)

above 120 90 118 I32 ll 1 I30 Fractional distillate of decene oligomer corresponding to the lubricating oil is 3571. "An example of the present invention.

DESCRIPTION OF THE PREFERRED EXAMPLE 5 EMBODIMENTS EXAMPLE l4 2,000 cc of an a-olefin mixture was charged into a four neck flask provided with a stirrer, cooler, nitrogen inlet tube and thermometer, and 4.3 of monoethyl aluminum dichloride and 21.0 g of titanium tetrachloride were added as catalysts, and polymerization was carried out. Keeping the temperature during the polymerization between to 40C, it was stirred for four hours.

After completing the reaction, ammonia gas was blown thereinto and the resulting precipitate was separated by filtration to remove the catalysts. The resulting crude reaction solution was distilled to remove unreacted olefins and the dimers and thereafter a fractional distillate corresponding to the working oil for aircraft was obtained. The cut of the fractional distillate was set so that the viscosity at 100F and the viscosity at 40F satisfy the standard MIL-B83282. Thereafter, it was hydrogenated with the use of Raney nickel as a catalyst at a temperature o'f 150C and under the condition of hydrogen pressure 20 Kg/cm to obtain working oil base having a performance shown in TABLE 2.

TABLE 2 (Example (Example (Example (Example Raw 1 2) 3) 4) Material Octene- 1 octene-l Octene-l Octene-l Olefin Decene-l Decene-l Nonene-l Decene-l Decene-l Olefin mixed C 60 C 50 C, 40 C, ratio C C 50 C 20 C 70 (mol7r) C 40 Average carbon 8.8 9.0 9.0 9.4 number Olefin conversion 80 81 79 77 Oligomer yield 70 72 69 68 Distillate corresponding to working 40 52 42 oil (for oligorner 7c) Viscosity 210F (CS) 4.00 4.05 4.01 4.08 Viscosity 100F (CS) 18.60 19.10 18.50 19.00 Viscosity 40F (CS) 2550 2500 2550 2400 Flash point (F) 420 440 440 440 Fire point (F) 476 480 480 485 Pour point (F) 80 80 80 75 Viscosity index 121 126 132 132 200 cc of diethyl ether was charged into the four neck distillation flask, and 17 g of aluminum chloride was added and dissolved. Thereafter, 3.1 g of lithium halide was added and a catalyst was prepared, and most of ethyl ether was distilled off, and 800 cc of a mixed a-olefins in which ocetene-l decene-l was 1 2 and 25 g of titanium tetrachloride were added.

The reaction was carried out for four hours at 100C-120C. After completing the reaction, according to the method in Example 1, distillation and hydrogenation were carried out to obtain a working oil base having a performance shown in Table 3.

What is claimed is:

1. In a method of producing a synthetic lubricating oil which comprises polymerizing a feed olefin by contacting said feed olefin with a catalyst system selected from the group consisting of (1) a catalyst complex prepared from a titanium halide and at least one kind of alkyl aluminum compound selected from the group consisting of AlR AlR AlR Cl and AlRCl wherein R is alkyl, and (2) a ternary catalyst consisting essentially of an alkali metal hydride compound, an aluminum halide and a titanium halide, the improvement which comprises:

said feed olefin contains from about to mole percent of a mixture of a-olefins selected from the group consisting of octene-l, nonene-l and decene-l, said mixture containing less than 30 mole percent of nonene-l and having an average carbon atom number in the range of 8.7 to 9.7, and the balance of the feed olefin is a-olefins of lower carbon atom number, and recovering from the polymerization reaction mixture a synthetic lubricating oil having a viscosity at 210F of above 3.5 centistokes, a viscosity at 100F of above 16.5 centistokes, a viscosity at 40F of below 2,600 centistokes, a flash point above 400F, a fire point above 475F, a pour point of below 65F and a viscosity index above 120.

2. A method according to claim l wherein said feed olefin consists of 100 mole percent of said mixture.

3. A method according to claim 1 wherein, in said a recovering step, the polymerization reaction is first treated to remove unreacted feed olefin and olefin dimers, then the remainder of the polymerization reaction mixture is fractionally distilled to recover a synthetic lubricating oil fraction and hydrogenating said fraction to obtain said synthetic lubricating oil.

halide1aluminum halide is from 120.5 to 1:2.

UNITED STATES PATENT. OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3 907 924 DATED I September 23, 1975 INVENTOR( 1 Hiroshi Isa et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 4; after "reaction" insert mixture-.

Column 8, line 8; change "in" (first occurrence) to --is--.

Signed and Scaled this twentye h Day f January 1976 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uj'larents and Trademarks 

1. IN A METHOD OF PRODUCING A SYNTHETIC LUBRICATING OIL WHICH COMPRISES POLYMERIZING A FEED OLEFIN BY CONTACTING SAID FEED OLEFIN WITH A CATALYST SYSTEM SELECTED FROM THE GROUP CONSISTING OF (1) A CATALYST COMPLEX PREPARED FROM A TITANIUM HADIDE AND AT LEAST ONE KIND OF ALKYL ALUMINUM COMPOUND SELECTED FROM THE GROUP CONSISTING OG AIR3 AIR2 AIR2.5 CL1.5 AND AIRCL2, WHEREIN R IS ALKYL, AND (2) A TERNARY CATALYST CONSISTIMG ESSENTIALLY OF ALKALI METAL HYDRIDE COMPOUND, AN ALUMINUM HALIDE AND A TITANIUM HALIDE THE IMPROVEMENT WHICH COMPRISES: SAID FEED OLEFIN CONTAINS FROM ABOUT 90 TO 100 MOLE PERCENT OF A MIXTURE OF A-OLEFINS SELECTED FROM THE GROUP CONSISTING OF OCETENE-1, NONEENE-1 AND DECENE-1,SAID MIXTURE CONTAINING LESS THAN 30 MOLE PERCENT OF NONENE-1 AND HAVING AN AVERAGE CARBON ATOM NUMBER IN THE RANGE OF 8.7 TO 9.7, AND THE BALANCE OF THE FED OLEFIN IS A-OLEFINS OF LOWER CARBON ATOM NUMBER AND RECOVERING FROM THE POLYMERIZATION REACTION MIXTURE A SYNTHETIC LUBRICATING OIL HAVING A VICOSITY AT 210*F OF ABOVE 3.5 CENTISTOKES, A VISCOSITY OF 100*F OF ABOVE 16.5 CENTISTOKES, A VISCOSITY AT -40* OF BELOW 2,600 CENTISTOKES, A FLASH POINT ABOVE 400*F A FREE POINT ABOVE 475*F, A POUR POINT OF BELOW -65*F AND A VICOSITY INDEX ABOVE
 120. 2. A method according to claim 1 wherein said feed olefin consists of 100 mole percent of said mixture.
 3. A method according to claim 1 wherein, in said recovering step, the polymerization reaction iS first treated to remove unreacted feed olefin and olefin dimers, then the remainder of the polymerization reaction mixture is fractionally distilled to recover a synthetic lubricating oil fraction and hydrogenating said fraction to obtain said synthetic lubricating oil.
 4. A method according to claim 1, in which said mixture has an average carbon atom number in the range of 8.8 to 9.2.
 5. A method according to claim 1 wherein the catalyst is said catalyst complex (1) having a molar ratio of Al:Ti in the range of 0.5 to 5.0:1.
 6. A method according to claim 1 in which the catalyst in said ternary catalyst (2) in which the molar ratio of alkali metal hydride compound:aluminum halide is from 1:0.5 to 1:6, and the molar ratio of titanium halide:aluminum halide is from 1:0.5 to 1:2. 